Legacy Immortality

"I swear to devote my life to the destruction of piracy, greed, cruelty, and injustice, in all their forms, and my sons and their sons shall follow me."

—Oath of the Skull, The Phantom

"Duffman can never die! (Beat) ...Only the actors who play him!"

—(A fatally wounded) Duffman, The Simpsons

A character is said to have lived for centuries; his name found all throughout the history books. When our hero or heroes finally meet him, he reveals his deepest, darkest secret—he's not actually immortal. As it turns out, he is merely the latest in a long line of Bob The Immortals. Apparently, the original Bob secretly trained a second to take up his name, appearance and personality. The second continued this with a third, and so on until present day. (There was always someone to Take Up My Sword, or for Passing the Torch to.)

This can be made much easier if first Bob The Immortal wore a mask all the time (possibly while claiming that the mask is what gives him immortality) or no one can agree on what the original looked like beyond 'he wears a Badass Longcoat and carries around a huge sword.'

This can also apply to Time Travellers, if they're sighted in multiple time periods and are thought to be immortal because of it.

Related to (and partially named for) Legacy Character. The primary difference between the two is that most Legacy Characters aren't attempting to appear immortal, but are instead Mythology Gags, promoted sidekicks, or simply revivals of older, forgotten characters. See also You Kill It, You Bought It. May overlap Shrouded in Myth.

The inversion (Bob the Immortal pretends to be a series of different people) is My Grandson, Myself.

Examples of Legacy Immortality include:

Anime and Manga

Code Geass: Zero will live on even though Lelouch is dead.
Tsukihime: The real Tohno Shiki, though it still doesn't save him most of the time.
Naruto has Madara. The real one died long ago, but Tobi was able to use the name to spark a new war.

Comic Books

In The Phantom, the main character is the 21st Phantom: All of them come from a single family where the son of the current Phantom becomes the next Phantom when the current one is killed. The page quote is sworn by each of them upon taking up the mantle. Since only a very select few are privy to this knowledge, and because of the Phantoms' tendencies to have cast-iron Character Shields, he is believed to be immortal by the natives of his home country and most of his foes.
The Confessor from Astro City turned into this. His sidekick picked up for him pretty seamlessly when the original was killed off. (It confuses the crooks a lot because the original actually was an immortal vampire who got dusted; his replacement, while not immortal, is also no longer bothered by garlic or crosses. This is implied to have low-level criminals around the city freaking the eff out, because they seem to think the Confessor actually came back from the dead invulnerable to traditional vampire weaknesses.)
- And Jack-In-The-Box from the same series has recruited an understudy for exactly this purpose when he realizes he's getting a bit old for the tights.
- And it's heavily implied that the Gentleman isn't actually ageless, but rather he was gradually replaced by his partner the Young Gentleman as he grew up.
In one of the ill-fated series offered by Atlas Comics in the 70's, it was left completely up in the air whether the Campbellian Hero was an immortal superman or the latest in a long (family) line of adventurers.
The main antagonist of the Blake and Mortimer two-part book The Sarcophagi of the Sixth Continent claims to be none other than the ancient Indian emperor Ashoka the Great. Mortimer met him during his youth in Colonial India and meets him again in 1958. However the latter Ashoka turns out to be the daughter of the former. We never learn who the previous Ashoka was, though...
Although it has never been seen through for any long period of time, Batman often hints, outright states or puts into action the idea that Batman must live even if he dies. This idea was the driving force behind the "Bat-Azrael" Dork Age.
- With Bruce Wayne's death/transportation back in time, Dick Grayson took up the Batman mantle in his place, holding onto it for a while even with Bruce's return to the cowl. While a lot of heroes were aware of the change - even guys like Booster Gold or Deadman - the villains seemed to be mostly oblivious.
- Batman Beyond was about Bruce making good on this promise through Terry McGinnis.
- Superman and Batman Generations plays with this by having the Bat-Family work to maintain the illusion that Batman has always been a single person, even when the mantle is passed from Bruce to Dick Grayson to Bruce Wayne Jr. and finally back to the original after he becomes immortal and takes up the job again in 1999.
In Iron Man Noir, Baron Strucker reveals that Baron Zemo isn't one person, but a series of chemically brainwashed men. Zemo wears a hood in case anyone recognizes him; the current Zemo is Howard Stark. Strucker hopes to turn Tony Stark into the next Zemo, since the one they have now has "outlived his resourcefulness."
Marvel Comics' Gorilla Man is a combination of Types II and VII: whoever kills him will become immortal, never aging, never getting sick. They can, however, be killed by someone else. The catch? Whoever kills Gorilla Man becomes the next Gorilla Man, and will have to put up with all the other people hunting down Gorilla Man for their shot at immortality - making this a variant Type VIII as well.

Fan Works

In The Teraverse, Camicia Rossa is an Italian crime-fighter who has been active since the 1860s. He is rumored to be immortal, but cynics suggest that he is actually many different men adopting the same identity and costume. The same is suggested as one explanation for the equally long criminal career of Fantômas.

Film

Ra's Al Ghul in Batman Begins, if we judge only by what is seen on screen. If you know about Ra's from other sources, Epileptic Trees suggest themselves.
- Well, it's actually implied that the "first" Ra's in the film was a decoy to begin with. Ducard was probably already Ra's. However, the second part is true: if you're familiar with Ra's outside the films, there are entirely different reasons why he would appear immortal.
  - Both could be the case. Ra's Al Ghul is a legacy character, held at the time of the film by Henri Ducard, who is also protected by a decoy in the form of Ken Watanabe's character.
  - More of a case that something as blatantly fantastic as the Lazarus Pits couldn't be in the realistic Nolanverse.
The 1967 version of Casino Royale outright states it in the case of James Bond, giving the code name to all the agents, but it's... non-canon, to say the least.
The Dread Pirate Roberts from The Princess Bride.

Literature

Inverted in the Belgariad, where the Tolnedrans think it's the case for Belgarath and Polgara, who are both genuine type two immortals.
- Another example in the same series is Queen Salmissra, though she's somewhat of a subversion as she was never intended to deceive the public. Instead it's the Nyissans' own absentminded god, because he forgot to make the original Salmissra immortal. He's not even very put out when someone finally sets things straight, so it's possible the entire ruse was never necessary in the first place.
A similar inversion occurs in the Deverry novels, where Nevyn keeps popping up at the side of key historical figures over the course of his 450-year existence. Opinions are divided as to whether the name of Nevyn is passed down from father to son or master to apprentice.
Also inverted in the Ender's Game series. Valentine is a published writer under the name "Demosthenes," and she was also born about a thousand years ago (although, through the anomalies of general relativity, she hasn't had any more years of subjective experience than any normal human). Because Demosthenes has been writing for a thousand years, he/she/they are believed to be this kind of legacy character, rather than all of the books and articles being written by the same person.
This is the story behind the villainous Mycroft Ward from The Raw Shark Texts.
Lampshaded in the Forgotten Realms novel Homeland, where a student assumes the identity of his dead master (who had a disfigured face), and briefly considers the possibility of the pattern continuing for millennia. It doesn't happen, though.
The titular (anti)hero of Santiago: A Myth of The Far Future. There have apparently been at least four 'Santiagos' and the book ends with a fifth.
The Dread Pirate Captain Roberts in The Princess Bride. When the old one decides to retire, he appoints his first mate as successor to the name. The one who came immediately before Wesley is noted to still be alive somewhere in South America, living like a king on the fortune he acquired as a pirate.

Live Action TV

In the first episode of the revived Doctor Who this is one theory about how come the same man was seen in various times (Titanic, JFK assassination, etc.)
In a later series of Red Dwarf it is revealed that Ace Rimmer is not one man, but a succession of hologram Rimmers from countless dimensions who have taken on his identity to continue the legacy of the original.
Christopher Chance in the current incarnation of Human Target is this.

Old Christopher Chance: Well it ain't really a name, least not one anyone was born into. I got it from the guy that taught me, he got it from the guy that taught him. 'Christopher Chance' is the guy you go to when no one else can help.

While the first season of Wonder Woman is set in World War II, the second season (referred to from there on as "The New Adventures of Wonder Woman") moves the setting to the present day. When Steve Trevor's son meets Wonder Woman, this is one of the theories he has for her looking the same after three decades. She of course, sets him straight.

Tabletop Games

In the first Ravenloft Gazetteer, the narrator S speculates that this is why stories of Harkon Lukas keep cropping up throughout Kartakan history: that the original Lukas had been such a successful bard that many others since have adopted his name as a means of self-promotion.

Video Games

In the first Fable, it is implied by an NPC that "Jack Of Blades" (the game's main villain) is not immortal, but several people wearing his robe and mask throughout the ages. In The Lost Chapters it is revealed that this is partially true -- Jack can possess people from beyond the grave if they put on his mask.
This is the explanation for Yoshimitsu appearing in both Tekken and Soulcalibur—the leader of the Manji clan adopts the name, personality, and fighting style, while using the same sword.
- Soulcalibur V lends even more credence to this, as the successor of the Yoshimitsu from SC to SCIV explicitly refers to himself as Yoshimitsu the Second.
In The Elder Scrolls IV: Oblivion, the Gray Fox works this way. He actually was many people in row wearing the same magical mask. The mask was cursed by the Daedra it was originally stolen from; wearing it permanently erases the wearer's identity from history, meaning nobody will ever recognize them (masked or not) as anyone other than the Gray Fox. After the curse is broken, the wearer is able to use the mask to perfectly mask his identity, but the mask can be removed and the effect will end.
Mass Effect 2 has the Shadow Broker, an unseen entity which commands a galaxy-spanning information network. The current Broker is Liara T'Soni, who took command secretly after killing her predecessor, an unnamed never-before-seen alien who did the exact same thing years before. The origin of the network is as-of-yet unknown.
In Zettai Hero Project, the Unlosing Ranger (a sendup of the entire Sentai genre of heroes) manages to achieve this. The tendency (at least for the past few exchanges) seems to be for a dying Unlosing Ranger to hand off the Morphing Belt to the best available passerby. Nobody ever picks up on this, at least not until the events of the game, where the latest recipient is laughably weak and unheroic.

Web Comics

The Crone of Maltak in Dominic Deegan.

Web Original

The Immortal Captain Roberto from Open Blue. It's All There in the Manual.
Major Liberty was the first costumed "superhero" in the Global Guardians PBEM Universe, having begun during the American Revolutionary War. The current Major Liberty is a direct descendant of the original (it is a family legacy). The general population think that it's been the same man all along.
Champion of the Whateley Universe. He's been around since the 1920's or 1930's, and he's powered by 'the Champion Force'. Only the current Champion is Champion VI, and there's another one in training at Super-Hero School Whateley Academy. When one Champion dies, he passes the Champion Force on to his successor who then gets the powers.

Western Animation

The animated Tarzan series simultaneously plays it straight and subverts it. Some elders in the native Waziri village claim to be hundreds of years old. It turns out, by the end of the episode, that they're referring to their family names, not the people themselves. But then, after the main characters are gone, the subversion is revealed: though not as old as they originally claimed, the actual elders are still far older than they look.
A villainous version in Gargoyles is The Hunter. The original was a scarred man who Demona clawed as a young boy; the title then passed to Prince Duncan and his descendants, who dedicated themselves to hunting her and other Gargoyles down.
- Except Demona knows that they're a family, having killed a good number of Hunters herself. She does sometimes use "the Hunter" to refer to the whole line, probably because there's not much difference between them all from her perspective.
In Recess, the school's pet hamster is constantly changed around - and nobody ever notices until one day, T.J. notices it die.

Real Life

Old Tom Parr probably used this technique.